全文获取类型
收费全文 | 1784篇 |
免费 | 115篇 |
国内免费 | 699篇 |
专业分类
安全科学 | 154篇 |
废物处理 | 105篇 |
环保管理 | 140篇 |
综合类 | 1039篇 |
基础理论 | 306篇 |
环境理论 | 1篇 |
污染及防治 | 630篇 |
评价与监测 | 79篇 |
社会与环境 | 49篇 |
灾害及防治 | 95篇 |
出版年
2024年 | 6篇 |
2023年 | 36篇 |
2022年 | 78篇 |
2021年 | 80篇 |
2020年 | 56篇 |
2019年 | 50篇 |
2018年 | 60篇 |
2017年 | 98篇 |
2016年 | 88篇 |
2015年 | 77篇 |
2014年 | 147篇 |
2013年 | 171篇 |
2012年 | 169篇 |
2011年 | 130篇 |
2010年 | 133篇 |
2009年 | 120篇 |
2008年 | 143篇 |
2007年 | 117篇 |
2006年 | 109篇 |
2005年 | 84篇 |
2004年 | 38篇 |
2003年 | 72篇 |
2002年 | 67篇 |
2001年 | 58篇 |
2000年 | 51篇 |
1999年 | 62篇 |
1998年 | 56篇 |
1997年 | 47篇 |
1996年 | 44篇 |
1995年 | 38篇 |
1994年 | 23篇 |
1993年 | 27篇 |
1992年 | 20篇 |
1991年 | 13篇 |
1990年 | 5篇 |
1989年 | 8篇 |
1988年 | 8篇 |
1987年 | 1篇 |
1986年 | 3篇 |
1985年 | 1篇 |
1984年 | 1篇 |
1982年 | 2篇 |
1981年 | 1篇 |
排序方式: 共有2598条查询结果,搜索用时 281 毫秒
331.
采用溶胶-凝胶法和浸渍法制备了Pd/CeZr/TiO2Al2O3蜂窝状金属丝网催化剂,并将其应用于在富氧条件下以丙烯选择催化还原NOx的研究.利用扫描电镜(SEM)分析了钛酸四丁酯的含量以及涂敷次数对TiO2涂层的影响,系统地考察了Pd含量、氧气浓度和空速对蜂窝状金属丝网催化剂催化性能的影响.实验结果表明,采用钛酸四丁酯的含量为20.0%的溶胶,涂敷2次,可以在金属丝网载体上氧化铝涂层表面获得均匀、无皲裂的TiO2涂层;Pd含量在0.23%~1.06%的范围内, NOx的转化率随Pd含量的增加而减小, Pd含量为0.23%时, NOx表现最高的NOx转化率;反应气体中氧气浓度从1.5%增加到6.0%, NOx的转化率随氧气浓度的增加而增大,当氧气浓度高于6.0%, NOx的转化率则随氧气浓度的增加而迅速减小; NOx的转化率随着空速的增加而降低,在高温条件下空速对转化率的影响要大于在低温条件下. 相似文献
332.
环糊精在土壤有机污染物治理中的应用 总被引:2,自引:0,他引:2
综述了环糊精及其衍生物在土壤弱极性有机物治理中的应用和原理。环糊精可与土壤中弱极性有机污染物形成主客包合物,从而增加其水溶性促进其从土壤中解吸去除;能够同时去除金属离子;能够改变有机污染物理化性质促进其光解;可降低有机污染物毒性促进其微生物降解。 相似文献
333.
Determination of polyfluoroalkyl compounds in water and suspended particulate matter in the river Elbe and North Sea, Germany 总被引:1,自引:0,他引:1
Lutz Ahrens Merle Plassmann Zhiyong Xie Ralf Ebinghaus 《Frontiers of Environmental Science & Engineering in China》2009,3(2):152-170
The distribution of polyfluoroalkyl compounds (PFCs) in the dissolved and particulate phase and their discharge from the river
Elbe into the North Sea were studied. The PFCs quantified included C4-C8 perfluorinated sulfonates (PFSAs), 6:2 fluorotelomer sulfonate (6:2 FTS), C6 and C8 perfluorinated sulfinates (PFSiAs), C4-C12 perfluorinated carboxylic acids (PFCAs), perfluoro-3,7-dimethyl-octanoic acid (3,7m2-PFOA), perfluorooctane sulfonamide (FOSA), and n-ethyl perfluroctane sulfonamidoethanol (EtFOSE). PFCs were mostly distributed
in the dissolved phase, where perfluorooctanoic acid (PFOA) dominated with 2.9–12.5 ng/L. In the suspended particulate matter
FOSA and perfluorooctane sulfonate (PFOS) showed the highest concentrations (4.0 ng/L and 2.3 ng/L, respectively). The total
flux of ΣPFCs from the river Elbe was estimated to be 802 kg/year for the dissolved phase and 152 kg/year for the particulate
phase. This indicates that the river Elbe acts as a source of PFCs into the North Sea. However, the concentrations of perfluorobutane
sulfonate (PFBS) and perfluorobutanoic acid (PFBA) in the North Sea were higher than that in the river Elbe, thus an alternative
source must exist for these compounds. 相似文献
334.
335.
施工现场管理水平高低直接影响着施工质量、安全和效益,特别是油水井大修侧钻、维护性作业,是体现队伍管理水平的重要标志。近年来,江苏油田分公司井下作业处作业一大队积极探索“四个到位”管理,推进作业现场标准化建设,提升安全管理水平。 相似文献
336.
337.
“平衡”是世间万物之本,而生态健康却与自然、社会、政治以及人体平衡等有着千丝万缕的联系。随着人类社会经济的不断发展和人们生活水平的不断提高,生态健康已成为现代化生活的一个重要标志,它直接关系到人们的健康生活。本文提出了“平衡”是生态健康之本,从一个新颖的视角一“平衡”,简明地论述了平衡在人类的生存发展过程中的重要性,以及它与生态健康之间的密切关系。文章中阐述的观点值得思考,对如何理解和审视“生态健康”有着重要的启示作用。 相似文献
338.
Liangliang Wei Kun Wang Qingliang Zhao Junqiu Jiang Chunmei Xie Wei Qiu 《环境科学学报(英文版)》2010,22(5):641-647
In order to characterize the organic properties of waste activated sludge in a wastewater treatment plant,organic matter within sludge was extracted with NH 3 ·H 2 O preferentially,and subsequently fractionated into five fractions using XAD-8/XAD-4 resins.Up to a 63.8%-71.1% of organic matter within the sludge could be efficiently extracted by NH 3 ·H 2 O.Fractionation results showed that hydrophobic acid and hydrophilic fraction were two main components among the sludge organic matter (accounting for 32.2% and 48.0% of the bulk organic matter,respectively),whereas transphilic acid,hydrophobic neutral and transphilic neutral were quite low (accounting for 9.2%,5.8% and 4.8%,respectively).Despite that the extractant of NH 3 ·H 2 O showed a relatively higher extraction efficiency of the aromatic components,the relatively low aromaticity of the organic fractions implied that those non-aromatic components could also be effectively extracted,especially for neutral and hydrophilic fractions.In addition,acidic fractions contained more aromatic humic-like components,whereas the neutral fractions had a greater content of aromatic proteins and soluble microbial byproduct-like components.Extraction of sludge organics with NH 3 ·H 2 O and subsequential fractionation using XAD resins could be a novel method for further characterization of sludge organics. 相似文献
339.
Youzhi Li Canming Zhang Yonghong Xie Fen Liu 《Mitigation and Adaptation Strategies for Global Change》2009,14(6):537-545
Deyeuxia angustifolia is a dominant species in the Sanjiang Plain, the largest freshwater marsh wetland in China. However, this species has declined
because of great environment changes. In the effects of sea-level rise and greenhouse gas, magnitude and frequency of flood
and rate of deposit in wetland increased greatly. Thus, in this paper, effects of soil environment (soil type, burial depth,
water depth and oxygen concentration) on seed germination of D. angustifolia were investigated. Both soil type and burial depth affected seedling emergence. Seedlings emerged through 1-, 2-, 4-mm sand,
and at 1-and 2-mm mud. Regardless of soil, seedling emergence time increased and emergence percentage decreased with increasing
burial depth. For example, seedlings started to emerge on the 4th day and the final emergence percentage was 30% when covered
with1-mm mud, whereas the initial emergence time was on the 6th day and the final emergence percentage was only 8% when covered
with 2-mm mud. At the same burial depth, emergence percentage was higher in sand than in mud. Increasing water depth inhibited
seed germination. Germination percentage in 2-cm water level (20%) was 1.2 times higher than that in 12-cm water level (9%).
Oxygen concentration also affected germination. In the 21% oxygen concentration, germination was started on the 2nd day and
the germination percentage was 36%, while seed started to germinate on the 4th day and the germination percentage was only
3% at the 7% oxygen concentration. These data indicate that seed germination of D. angustifolia was highly sensitive to soil type, burial depth, water depth, oxygen concentration, and these responses may be an explicit
indication of maladjustment to environment changes, and an important reason accounting for the decline of this species in
the Sanjiang Plain. 相似文献
340.
高度有序的TiO2纳米管阵列光催化性能研究 总被引:2,自引:2,他引:0
采用恒压阳极氧化法在纯钛箔表面制备TiO2纳米管阵列,利用SEM和XRD对其进行了形貌和晶型的分析和表征,并通过TiO2纳米管阵列膜对甲基橙光催化降解,探讨光照时间、甲基橙溶液的初始浓度、溶液的初始pH值和H2O2加入浓度等因素对甲基橙的脱色率影响.结果表明,H2O2加入浓度为50mg·L-1,紫外光照射2h,溶液为中性时,在30 mg·L-1的甲基橙溶液(50mL)中,甲基橙溶液的脱色率达到100%.当H2O2加入浓度进一步增大到100 mg·L-1时,光催化的效率进一步提高,紫外光照射1h,甲基橙溶液的脱色率就已经达到了100%,并未出现抑制光催化的现象.同时还研究了TiO2纳米管阵列电极的稳定性.实验结果表明,随着TiO2纳米管阵列使用次数的增加,其光催化效果略有所下降. 相似文献